The indictment – a formal accusation that moves the case to trial – charges them with conspiracy and securities fraud.

Both billionaire Rajaratnam, 52, and Chiesi, who is a former consultant to New Castle Partners LLC, deny the charges.

The indictment marks the first set of criminal charges in relation to the Securities and Exchange Commission (SEC) accusations, which have led to 21 arrests and allege insider trading in securities for top companies such as Google, Intel, Hilton and AMD.

Rajaratnam was arrested on 16 October. He is free on bail and will appear in Manhattan federal court in coming days to enter a plea.